Mrs. Jones, daughter also of the late Hjalmar Unander-Scharin of Stockholm, Sweden, is an alumna of the Garrison (Md.) Forest School. Her previous marriage terminated in divorce.
The prospective bridegroom was graduated from the Hotchkiss School in Lakeville, Conn., and in 1950 from the University of Pennsylvania. He returned recently from Korea after serving as a first lieutenant in the Marine Corps.
Mr. Mirkil is a member of the Racquet Club of Philadelphia, the Merion Cricket Club and the Merion Golf Club.